An internal-combustion engine is known that consists of a rotating block of a rotational shape, with radially situated cylinders with pistons. Outside the rotating cylinder block there is a stationary case with intake and exhaust ports and so the rotational cylinder block together with the stationary case work like a rotary valve. Pistons are connected with a crankshaft by means of connecting rods. The crankshaft rotates at different revolutions than the rotating cylinder block and they are coupled by means of gearing.
There are known designs of two, three and multi cylinder arrangements of engines with rotating block of the rotational shape with radially situated cylinders with pistons. Outside this rotating cylinder block there is a stationary case with intake and exhaust ports. The rotating cylinder block serves as a rotary valve at the same time. Pistons are connected with the engine crankshaft by means of any of known mechanisms for converting straight movement of a piston to the rotating one of a crankshaft. The engine crankshaft is coupled with the rotating cylinder block by means of gearing. None of those designs has achieved wider enlargement and utilization despite the undoubted potential.
There are many reasons why these engines were not successful. These engines were designed with usual bore/stroke ratio and the engine dimensions were then too large. Rotation of a big block is then problematic in terms of high inertia forces, deformation of the big outer stationary case, cylinder cooling etc. Another negative feature of these designs was the seal between the rotating block and the stationary case. The cylinder space was mostly sealed to the stationary case by a seal, which was placed in the rotating cylinder block. This seal was then exposed to centrifugal forces that are caused by rotation of the cylinder block. That seal was consequently more loaded, there were high friction losses and lubrication problems. Such designs are described e.g. in patents DE2732779, DE2153946A1 or FR2767156A1.